Fallon, along with the graduates, wore a stole which read "MSD Strong." During his speech, the host combined his signature humor with some inspiring words and praise for the students' response to the tragedy.

"Today you are graduating from high school. You should feel incredibly proud of yourselves," Fallon told students. "That doesn't mean you should rest on your laurels — or your yannys."

The host went on to recall his experience at the March For Our Lives in Washington, D.C., earlier this year, where he met many of the students and their teachers. "My wife and I brought our two little girls because we wanted them to see what hope and light looks like," he shared.

Fallon also recalled a time when he was younger and had to attend summer school. Although he was disappointed at the prospect, he ended up enjoying the experience because he met other students who were funny like him. "Sometimes, things that seem like setbacks can take our lives in a totally new direction and can changes us in ways we don't expect," he told the crowd. "And they make us better and stronger."

Fallon ended his speech with a more serious version of his "Thank You Notes" segment from The Tonight Show. "Thank you for showing me, and the rest of the world, that there is hope," he said, adding, "Most commencement speakers, they say, 'You are the future.' But I'm not gonna say that, because you're not the future. You're the present."

The host's speech wasn't the only powerful moment during the ceremony. Four seniors who were killed in the shooting — Nicholas Dworet, Joaquin Oliver, Meadow Pollack, and Carmen Schentrup — earned posthumous diplomas, which were accepted by their families. According to the Huffington Post, Oliver's mother Patricia wore a shirt on stage which read, "This should be my son."